Chardy’s elation was nearly replaced with dejection after del Potro forced a fifth set, but the Argentine’s hopes for his first win from two sets down would be denied. The Frenchman stopped the 2009 US Open champion from completing the comeback by securing the only break to go up 5-3 and clinching the victory after three hours and 45 minutes with an ace, finishing the match with 78 winners to 36 for del Potro.

“It's not a good result after coming back from two sets down,” said del Potro. “But Jeremy played really well in the fifth set. He deserved to win the match. He broke my serve. He was so calm to close the match in the end.”

Chardy went on to reach his first major quarter-final and attained a career-high Emirates ATP Ranking of No. 25 following the Australian Open. Del Potro would suffer another early upset at the US Open, falling in five sets in his second round match against childhood idol Lleyton Hewitt.

9. Karen Khachanov d. Janko Tipsarevic 6-4, 6-4, Moscow 2nd RDIt didn’t take long for 17-year-old Russian Karen Khachanov to make an impression. Playing in just his third tour-level event, the recent high school graduate surprised former World No. 8 Janko Tipsarevic at the Kremlin Cup, causing former World No. 1 Yevgeny Kafelnikov to remark, “He will be Top 20 [in the Emirates ATP Rankings] by end of 2015.”

The 6’6” Khachanov, who made a winning tour-level debut a month earlier against Victor Hanescu in St. Petersburg, did not face any break points and served 14 aces in a 77-minute win over 2011 champion Tipsarevic. Coupled with his opening win over Albert Ramos, Khachanov became the youngest quarter-finalist on the ATP World Tour since 2007.

“I didn’t really believe I had beaten Tipsarevic,” said Khachanov, who won the European Junior Championships in July. “It has been a good bonus to see what I can do against the pros. It has given me the confidence and the opportunity to play better.”

8. Vasek Pospisil d. Tomas Berdych 7-5, 2-6, 7-6(5), Montreal 3rd RDHome advantage carried Vasek Pospisil during a memorable two-week stretch in August. The 23-year-old British Columbia native won the Vancouver Challenger, and followed with a surprise run at the Coupe Rogers, where he met Milos Raonic in the first all-Canadian semi-final in the Open Era.

Pospisil’s breakthrough week on the ATP World Tour included wins over three former Top 10 players - John Isner, Radek Stepanek and Nikolay Davydenko - but the highlight came against World No. 6 Tomas Berdych in the third round. As he had done in his opener against Isner, resulting in his first Top 20 win, Pospisil prevailed in a third-set tie-break.

The Canadian, who had conceded a break lead earlier in the set, won the final three points in his first match against a Top 10 player. He celebrated the two hour, 37-minute victory as the 3,000-strong crowd on National Bank Court broke out into “Ole!” - normally sung by fans at Montreal Canadiens hockey games.

“This was definitely the most emotional ending and best match of my career, without a doubt,” said Pospisil. “I don’t really know what’s going on now. To have my first Top 10 win here, in front of that crowd, was extremely emotional. I was having difficulty controlling it.”

7. Tommy Haas d. Novak Djokovic 6-2, 6-4, Miami 4th RDThe odds were not in Tommy Haas’ favour entering his fourth-round match against Novak Djokovic at the Sony Open Tennis. Haas had not beaten a World No. 1 in 14 years since upsetting Andre Agassi at the 1999 Grand Slam Cup - in fact his lone victory against 14 losses - and Djokovic had won 14 straight matches in Miami as the two-time defending champion.

But just eight days before his 35th birthday, Haas came out on top against the ATP’s top-ranked player after just 80 minutes in Tuesday’s night’s marquee match. Though he was broken at love while serving up 3-2 in the second set, the German regrouped to win three of the final four games, becoming the oldest player in 30 years to beat the World No. 1.

“These are the moments I appreciate the most, going on those big stadiums, big stages, playing against the best people in the world,” said Haas. “Playing against someone like Novak and coming out on top at this time of my career, it's unbelievable. It goes up as one of [the] best wins of my career.”

6. Joao Sousa d. David Ferrer 6-2, 7-6(6), Kuala Lumpur QFsJoao Sousa made history as the first Portuguese player to win an ATP World Tour title by defeating Frenchman Julien Benneteau in the Malaysian Open, Kuala Lumpur final. His biggest test, however, came in the quarter-finals, when he faced off against World No. 4 David Ferrer.

Riding the momentum of his first tour-level semi-final the previous week in St. Petersburg, the 77th-ranked Sousa capitalised on all three of his break points against the top seed. Sousa was broken as he served for the victory at 5-4, but rallied from a 4-6 deficit in the tie-break to clinch his biggest career win after one hour and 38 minutes.

“I just went for it,” reflected the 24 year old. “I played an amazing match and he did not play his best. [Playing] tennis like that I was really happy to beat David.”